Fluval Poly/Carbon Cartridge (2 pack)
Pack size
2 cartridges
Fits
Fluval U2 Underwater Filter (variant U2, part A490), Fluval U3 Underwater Filter (variant U3, part A491)
Replace every
1 months
Media type
Poly floss
Fluval Poly/Carbon Cartridge (2 pack)
Genuine Fluval poly/carbon cartridges for the U2 or U3 underwater filter, combining mechanical and chemical filtration in one cartridge. Each pack holds two cartridges – one poly-floss face to trap fine debris, one activated-carbon face to pull colour and odour out of the water – sized to drop straight into the U2 or U3 media basket.
Key features
- Two-stage cartridge – polyester floss for mechanical filtration, activated carbon for chemical filtration, in one drop-in piece.
- Genuine Fluval fit – sized specifically for the U2 (part A490) or U3 (part A491) media basket, sold as separate variants.
- 2 cartridges per pack – enough for two monthly changes.
- No rinsing or soaking – drops straight in and is discarded when spent.
Will it fit my filter?
| Variant | Fits | Part number |
|---|---|---|
| U2 | Fluval U2 Underwater Filter | A490 |
| U3 | Fluval U3 Underwater Filter | A491 |
The U2 and U3 cartridges are sized differently and are not interchangeable – order the variant that matches your filter model, printed on the filter body.
Specifications
| Pack size | 2 cartridges |
|---|---|
| Media type | Poly floss (mechanical) + activated carbon (chemical), combined |
| Replacement interval | Monthly |
Care and maintenance
Fluval's own filter manual specifies replacing the poly/carbon cartridge monthly on U2, U3 and U4 filters. Carbon only removes colour and odour for a few weeks before it exhausts and starts releasing what it's trapped back into the water, so leaving a cartridge in past that point does more harm than good.
Suitable for and not suitable for
Suitable for routine monthly media changes on a U2 or U3 filter. Not suitable if you're dosing medication in the same tank – activated carbon will strip most medications out of the water, so remove the cartridge before treating and replace it once the course is finished.
Warranty and delivery
Covered by Fluval's standard replacement-parts warranty against manufacturing defects, in addition to your rights under Australian Consumer Law. Standard freight.
Common questions
How often should I change this cartridge?
Monthly, per Fluval's own maintenance guidance for the U2/U3/U4 range.
Is the U2 cartridge the same as the U3 cartridge?
No – they're sized for each filter's media basket and sold as separate variants (A490 for U2, A491 for U3).
Should I remove it while treating with medication?
Yes – activated carbon will absorb most medications, reducing their effectiveness.
Do I need to rinse it before use?
No – it's ready to drop straight into the media basket.
